please do not use answers previous answered used on chegg, they are incorrect. thank you!

One mole of octane (C8H18) fuels an internal combustion engine. When the octane burns in a cylinder the piston moves upward, as shown below. (Assume that air is an ideal gas and is 80%N2 and 20%O2.) Note that ALL of the O2 is used in the reaction. nswer the following questions using the data below. Assume that the heat capacities are constant over this temperature range. Be sure to use the correct sign for uestions 4 and 5 . How much work is performed by the gas? ( JJ) (Hint: The answer is a negative number.) QUESTION 5 What is the change in internal energy (U) for the gas in the cylinder? (kJ)